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Dickeson SK, Kumar S, Sun MF, Litvak M, He TZ, Phillips DR, Roberts ET, Feener EP, Law RHP, Gailani D. A mechanism for hereditary angioedema caused by a methionine-379-to-lysine substitution in kininogens. Blood 2024; 143:641-650. [PMID: 37992228 PMCID: PMC10873535 DOI: 10.1182/blood.2023022254] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/20/2023] [Accepted: 11/13/2023] [Indexed: 11/24/2023] Open
Abstract
ABSTRACT Hereditary angioedema (HAE) is associated with episodic kinin-induced swelling of the skin and mucosal membranes. Most patients with HAE have low plasma C1-inhibitor activity, leading to increased generation of the protease plasma kallikrein (PKa) and excessive release of the nanopeptide bradykinin from high-molecular-weight kininogen (HK). However, disease-causing mutations in at least 10% of patients with HAE appear to involve genes for proteins other than C1-inhibitor. A point mutation in the Kng1 gene encoding HK and low-molecular weight kininogen (LK) was identified recently in a family with HAE. The mutation changes a methionine (Met379) to lysine (Lys379) in both proteins. Met379 is adjacent to the Lys380-Arg381 cleavage site at the N-terminus of the bradykinin peptide. Recombinant wild-type (Met379) and variant (Lys379) versions of HK and LK were expressed in HEK293 cells. PKa-catalyzed kinin release from HK and LK was not affected by the Lys379 substitutions. However, kinin release from HK-Lys379 and LK-Lys379 catalyzed by the fibrinolytic protease plasmin was substantially greater than from wild-type HK-Met379 and LK-Met379. Increased kinin release was evident when fibrinolysis was induced in plasma containing HK-Lys379 or LK-Lys379 compared with plasma containing wild-type HK or LK. Mass spectrometry revealed that the kinin released from wild-type and variant kininogens by PKa is bradykinin. Plasmin also released bradykinin from wild-type kininogens but cleaved HK-Lys379 and LK-Lys379 after Lys379 rather than Lys380, releasing the decapeptide Lys-bradykinin (kallidin). The Met379Lys substitutions make HK and LK better plasmin substrates, reinforcing the relationship between fibrinolysis and kinin generation.
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Affiliation(s)
- S. Kent Dickeson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Sunil Kumar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Mao-fu Sun
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Maxim Litvak
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | - Tracey Z. He
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
| | | | | | | | - Ruby H. P. Law
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - David Gailani
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN
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