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Presence of C1-inhibitor polymers in a subset of patients suffering from hereditary angioedema.

Madsen DE, Hansen S, Gram J, Bygum A, Drouet C, Sidelmann JJ - PLoS ONE (2014)

Bottom Line: Subjects suffering from HAE have been classified in type I patients with decreased functional and antigenic levels of C1-inh, and type II patients with decreased functional but normal antigenic C1-inh levels.Using this approach we analyzed genuine plasma samples from 31 Danish HAE families, and found that plasma samples from three genotypically distinct HAE type I families (classified upon C1-inh plasma concentrations) contained C1-inh polymers.In conclusion, we demonstrate that C1-inh polymers are present in the plasma of a subgroup of HAE type I patients.

View Article: PubMed Central - PubMed

Affiliation: University of Southern Denmark, Institute of Public Health, Unit for Thrombosis Research, Esbjerg, Denmark.

ABSTRACT
Hereditary angioedema (HAE) is a potentially life-threatening disease caused by mutations in the gene encoding the serine protease inhibitor (serpin) C1 inhibitor (C1-inh). The mutations cause decreased functional plasma levels of C1-inh, which triggers unpredictable recurrent edema attacks. Subjects suffering from HAE have been classified in type I patients with decreased functional and antigenic levels of C1-inh, and type II patients with decreased functional but normal antigenic C1-inh levels. However, a few reports have demonstrated that some mutations cause C1-inh polymerization in vitro, and it is speculated that C1-inh polymers may exist in patient plasma, challenging the current classification of HAE patients. To investigate the presence of C1-inh polymers in patient plasma samples, we developed an immunological method, where monoclonal antibodies produced against polymerized C1-inh were applied in native PAGE western blotting. Using this approach we analyzed genuine plasma samples from 31 Danish HAE families, and found that plasma samples from three genotypically distinct HAE type I families (classified upon C1-inh plasma concentrations) contained C1-inh polymers. Identical C1-inh polymerization phenotypes were observed in four affected family members from one of these families. Genotyping of the families revealed that the polymerogenic mutations of two families were located in proximity to the reactive center loop insertion site in C1-inh (p.Ile271Thr and p.Ser258_Pro260del),and one mutation affected helix C (p.Thr167Asn). In conclusion, we demonstrate that C1-inh polymers are present in the plasma of a subgroup of HAE type I patients.

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Related in: MedlinePlus

PAGE analysis of native and polymerized C1-inh.A) Native PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2) and native C1-inh (lane 3). Proteins were visualized using silver staining. B): SDS PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2), native C1-inh (lane3) and a molecular weight marker (lane M). Molecular weights of the marker proteins are depicted in kDa to the right. Proteins were visualized using silver staining.
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pone-0112051-g001: PAGE analysis of native and polymerized C1-inh.A) Native PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2) and native C1-inh (lane 3). Proteins were visualized using silver staining. B): SDS PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2), native C1-inh (lane3) and a molecular weight marker (lane M). Molecular weights of the marker proteins are depicted in kDa to the right. Proteins were visualized using silver staining.

Mentions: Polymerization of C1-inh was visualized using native PAGE analysis (Fig. 1A). The pC1-inh preparation contained polymers of various sizes, and the electrophoretic mobility of pC1-inh remained unaffected by the BS3 conjugation. Trace amounts of monomeric C1-inh were observed in the two polymerized samples. The molecular weight of BS3 conjugated C1-inh polymers (Fig. 1B). corresponded to those anticipated for C1-inh polymers. pC1-inh was not SDS-stable, but dissolved to the monomeric form when boiled in the presence of SDS.


Presence of C1-inhibitor polymers in a subset of patients suffering from hereditary angioedema.

Madsen DE, Hansen S, Gram J, Bygum A, Drouet C, Sidelmann JJ - PLoS ONE (2014)

PAGE analysis of native and polymerized C1-inh.A) Native PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2) and native C1-inh (lane 3). Proteins were visualized using silver staining. B): SDS PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2), native C1-inh (lane3) and a molecular weight marker (lane M). Molecular weights of the marker proteins are depicted in kDa to the right. Proteins were visualized using silver staining.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4219832&req=5

pone-0112051-g001: PAGE analysis of native and polymerized C1-inh.A) Native PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2) and native C1-inh (lane 3). Proteins were visualized using silver staining. B): SDS PAGE analysis of BS3 conjugated pC1-inh (lane 1), pC1-inh (lane 2), native C1-inh (lane3) and a molecular weight marker (lane M). Molecular weights of the marker proteins are depicted in kDa to the right. Proteins were visualized using silver staining.
Mentions: Polymerization of C1-inh was visualized using native PAGE analysis (Fig. 1A). The pC1-inh preparation contained polymers of various sizes, and the electrophoretic mobility of pC1-inh remained unaffected by the BS3 conjugation. Trace amounts of monomeric C1-inh were observed in the two polymerized samples. The molecular weight of BS3 conjugated C1-inh polymers (Fig. 1B). corresponded to those anticipated for C1-inh polymers. pC1-inh was not SDS-stable, but dissolved to the monomeric form when boiled in the presence of SDS.

Bottom Line: Subjects suffering from HAE have been classified in type I patients with decreased functional and antigenic levels of C1-inh, and type II patients with decreased functional but normal antigenic C1-inh levels.Using this approach we analyzed genuine plasma samples from 31 Danish HAE families, and found that plasma samples from three genotypically distinct HAE type I families (classified upon C1-inh plasma concentrations) contained C1-inh polymers.In conclusion, we demonstrate that C1-inh polymers are present in the plasma of a subgroup of HAE type I patients.

View Article: PubMed Central - PubMed

Affiliation: University of Southern Denmark, Institute of Public Health, Unit for Thrombosis Research, Esbjerg, Denmark.

ABSTRACT
Hereditary angioedema (HAE) is a potentially life-threatening disease caused by mutations in the gene encoding the serine protease inhibitor (serpin) C1 inhibitor (C1-inh). The mutations cause decreased functional plasma levels of C1-inh, which triggers unpredictable recurrent edema attacks. Subjects suffering from HAE have been classified in type I patients with decreased functional and antigenic levels of C1-inh, and type II patients with decreased functional but normal antigenic C1-inh levels. However, a few reports have demonstrated that some mutations cause C1-inh polymerization in vitro, and it is speculated that C1-inh polymers may exist in patient plasma, challenging the current classification of HAE patients. To investigate the presence of C1-inh polymers in patient plasma samples, we developed an immunological method, where monoclonal antibodies produced against polymerized C1-inh were applied in native PAGE western blotting. Using this approach we analyzed genuine plasma samples from 31 Danish HAE families, and found that plasma samples from three genotypically distinct HAE type I families (classified upon C1-inh plasma concentrations) contained C1-inh polymers. Identical C1-inh polymerization phenotypes were observed in four affected family members from one of these families. Genotyping of the families revealed that the polymerogenic mutations of two families were located in proximity to the reactive center loop insertion site in C1-inh (p.Ile271Thr and p.Ser258_Pro260del),and one mutation affected helix C (p.Thr167Asn). In conclusion, we demonstrate that C1-inh polymers are present in the plasma of a subgroup of HAE type I patients.

Show MeSH
Related in: MedlinePlus