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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Categories: 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 1

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Identification of mutant factor H protein in serum of HUS patients. (a) ...
Identification of mutant factor H protein in serum of HUS patients. (a) Sera from normal individual (control) (lane 1) and HUS patients with the R1210C (F106, lane 2), the R1215G (F34, lane 3), and the E1172Stop mutation (R043, lane 4) were separated by SDS-PAGE and assayed by Western blotting using anti–factor H antiserum. Note the band with 175 kDa depicted by the arrow in serum of patient F106 (lane 2). Serum derived from patient F34 with the R1215G mutation showed normal factor H, and no additional band was detected. In serum from patient with the E1172Stop mutation (R043), a band of higher mobility with a reduced molecular weight is identified. (b) Reactivity of the normal plasma factor H and the 175 band with antisera and mAb’s specific for factor H. Sera from a healthy individual (lanes 1–3) and patient F106 with the R1210C mutation (lanes 4–10) were separated by SDS-PAGE, and after Western blotting, reacted with the indicated polyclonal and monoclonal Ab’s (lanes 1, 4). (c) Western blotting and (d) silver staining of reduced and deglycosylated (N-glycosidase F; GF) control and patient samples.