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Grafting of thrombopoietin‐mimetic peptides into cystine knot miniproteins yields high‐affinity thrombopoietin antagonists and agonists
Author(s) -
Krause Sebastian,
Schmoldt HansUlrich,
Wentzel Alexander,
Ballmaier Matthias,
Friedrich Karlheinz,
Kolmar Harald
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05567.x
Subject(s) - thrombopoietin , thrombopoietin receptor , megakaryocyte , agonist , chemistry , receptor , biochemistry , biology , pharmacology , microbiology and biotechnology , stem cell , haematopoiesis
Thrombopoietin is the primary regulator of platelet production. We exploited two naturally occurring miniproteins of the inhibitor cystine knot family as stable and rigid scaffolds for the incorporation of peptide sequences that have been shown to act as high‐affinity thrombopoietin antagonists. Several miniproteins that antagonistically block thrombopoietin‐mediated receptor activation were identified using a microscale reporter assay. Covalent miniprotein dimerization yielded potent bivalent c‐Mpl receptor agonists with EC 50 values in the low nanomolar or picomolar range. One selected miniprotein‐derived thrombopoietin agonist was almost as active as natural thrombopoietin with regard to stimulation of megakaryocyte colony formation from human bone marrow mononuclear cells, and elicited doubling of platelet counts in mice. Our data suggest that dimeric cystine knot miniproteins have considerable potential for the future development of small and stable receptor agonists. This approach may provide a promising strategy for pharmaceutical interference with other receptors activated by ligand‐induced dimerization.