Mutations in factor H reduce binding affinity to C3b and heparin and surface attachment to endothelial cells in hemolytic uremic syndrome
Tamara Manuelian, … , Giuseppe Remuzzi, Peter F. Zipfel
Tamara Manuelian, … , Giuseppe Remuzzi, Peter F. Zipfel
Published April 15, 2003
Citation Information: J Clin Invest. 2003;111(8):1181-1190. https://doi.org/10.1172/JCI16651.
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Article Nephrology

Mutations in factor H reduce binding affinity to C3b and heparin and surface attachment to endothelial cells in hemolytic uremic syndrome

Abstract

Hemolytic uremic syndrome (HUS) is a disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Recent studies have identified a factor H–associated form of HUS, caused by gene mutations that cluster in the C-terminal region of the complement regulator factor H. Here we report how three mutations (E1172Stop, R1210C, and R1215G; each of the latter two identified in three independent cases from different, unrelated families) affect protein function. All three mutations cause reduced binding to the central complement component C3b/C3d to heparin, as well as to endothelial cells. These defective features of the mutant factor H proteins explain progression of endothelial cell and microvascular damage in factor H–associated genetic HUS and indicate a protective role of factor H for tissue integrity during thrombus formation.

Authors

Tamara Manuelian, Jens Hellwage, Seppo Meri, Jessica Caprioli, Marina Noris, Stefan Heinen, Mihaly Jozsi, Hartmut P.H. Neumann, Giuseppe Remuzzi, Peter F. Zipfel

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Figure 2

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The mutant form of factor H binds less efficiently to heparin. Sera from...
The mutant form of factor H binds less efficiently to heparin. Sera from a healthy control (a) and from HUS patient F106 with the R1210C mutation (b) were applied to heparin affinity chromatography, and after washing, bound proteins were eluted with the linear NaCl gradient. Individual fractions of 500 μl were collected starting at an NaCl concentration of 200 mM. The fractions were assayed by SDS-PAGE in combination with Western blotting. The 175-kDa mutant factor H eluted at a lower salt concentration (fraction 35) prior to the wild-type factor H protein (fraction 41). The arrow indicates the position of the mutant factor H protein.