%0 Journal Article %1 Harder:2016jfb %A Harder, Markus J %A Anliker, Markus %A Höchsmann, Britta %A Simmet, Thomas %A Huber-Lang, Markus %A Schrezenmeier, Hubert %A Ricklin, Daniel %A Lambris, John D. %A Barlow, Paul N %A Schmidt, Christoph Q %D 2016 %J Journal of immunology (Baltimore, Md. : 1950) %K imported %N 2 %P 866--876 %R 10.4049/jimmunol.1501919 %T Comparative Analysis of Novel Complement-Targeted Inhibitors, MiniFH, and the Natural Regulators Factor H and Factor H-like Protein 1 Reveal Functional Determinants of Complement Regulation. %U http://www.jimmunol.org/lookup/doi/10.4049/jimmunol.1501919 %V 196 %X The serum proteins factor H (FH), consisting of 20 complement control protein modules (CCPs), and its splice product FH-like protein 1 (FHL-1; consisting of CCPs 1-7) are major regulators of the alternative pathway (AP) of complement activation. The engineered version of FH, miniFH, contains only the N- and C-terminal portions of FH linked by an optimized peptide and shows ∼ 10-fold higher ex vivo potency. We explored the hypothesis that regulatory potency is enhanced by unmasking of a ligand-binding site in the C-terminal CCPs 19-20 that is cryptic in full-length native FH. Therefore, we produced an FH variant lacking the central domains 10-15 (FH$\Delta$10-15). To explore how avidity affects regulatory strength, we generated a duplicated version of miniFH, termed midiFH. We compared activities of FH$\Delta$10-15 and midiFH to miniFH, FH, and FHL-1. Relative to FH, FH$\Delta$10-15 exhibited an altered binding profile toward C3 activation products and a 5-fold-enhanced complement regulation on a paroxysmal nocturnal hemoglobinuria patient's erythrocytes. Contrary to dogma, FHL-1 and FH exhibited equal regulatory activity, suggesting that the role of FHL-1 in AP regulation has been underestimated. Unexpectedly, a substantially increased avidity for complement opsonins, as seen in midiFH, did not potentiate the inhibitory potential on host cells. In conclusion, comparisons of engineered and native FH-based regulators have identified features that determine high AP regulatory activity on host cells. Unrestricted availability of FH CCPs 19-20 and an optimal spatial orientation between the N- and C-terminal FH regions are key.

@article{Harder:2016jfb, abstract = {The serum proteins factor H (FH), consisting of 20 complement control protein modules (CCPs), and its splice product FH-like protein 1 (FHL-1; consisting of CCPs 1-7) are major regulators of the alternative pathway (AP) of complement activation. The engineered version of FH, miniFH, contains only the N- and C-terminal portions of FH linked by an optimized peptide and shows ∼ 10-fold higher ex vivo potency. We explored the hypothesis that regulatory potency is enhanced by unmasking of a ligand-binding site in the C-terminal CCPs 19-20 that is cryptic in full-length native FH. Therefore, we produced an FH variant lacking the central domains 10-15 (FH$\Delta$10-15). To explore how avidity affects regulatory strength, we generated a duplicated version of miniFH, termed midiFH. We compared activities of FH$\Delta$10-15 and midiFH to miniFH, FH, and FHL-1. Relative to FH, FH$\Delta$10-15 exhibited an altered binding profile toward C3 activation products and a 5-fold-enhanced complement regulation on a paroxysmal nocturnal hemoglobinuria patient's erythrocytes. Contrary to dogma, FHL-1 and FH exhibited equal regulatory activity, suggesting that the role of FHL-1 in AP regulation has been underestimated. Unexpectedly, a substantially increased avidity for complement opsonins, as seen in midiFH, did not potentiate the inhibitory potential on host cells. In conclusion, comparisons of engineered and native FH-based regulators have identified features that determine high AP regulatory activity on host cells. Unrestricted availability of FH CCPs 19-20 and an optimal spatial orientation between the N- and C-terminal FH regions are key.}, added-at = {2017-12-08T05:18:19.000+0100}, affiliation = {Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany;}, author = {Harder, Markus J and Anliker, Markus and H{\"o}chsmann, Britta and Simmet, Thomas and Huber-Lang, Markus and Schrezenmeier, Hubert and Ricklin, Daniel and Lambris, John D. and Barlow, Paul N and Schmidt, Christoph Q}, biburl = {https://www.bibsonomy.org/bibtex/2f02ca408bffe7f2228ccaed5db2cb9b7/lambris}, date-added = {2017-12-08T04:15:46GMT}, date-modified = {2017-12-08T04:17:38GMT}, doi = {10.4049/jimmunol.1501919}, interhash = {e5cda136267447022bcec618ecef8a8d}, intrahash = {f02ca408bffe7f2228ccaed5db2cb9b7}, journal = {Journal of immunology (Baltimore, Md. : 1950)}, keywords = {imported}, language = {English}, month = jan, number = 2, pages = {866--876}, pmcid = {PMC4707092}, pmid = {26643478}, rating = {0}, timestamp = {2017-12-08T05:18:19.000+0100}, title = {{Comparative Analysis of Novel Complement-Targeted Inhibitors, MiniFH, and the Natural Regulators Factor H and Factor H-like Protein 1 Reveal Functional Determinants of Complement Regulation.}}, uri = {\url{papers3://publication/doi/10.4049/jimmunol.1501919}}, url = {http://www.jimmunol.org/lookup/doi/10.4049/jimmunol.1501919}, volume = 196, year = 2016 }