Publikation

Complement and atherogenesis: binding of CRP to degraded, nonoxidized LDL enhances complement activation

Wissenschaftlicher Artikel/Review - 01.10.1999

PubMed

Zitation
Bhakdi S, Torzewski M, Klouche M, Hemmes M. Complement and atherogenesis: binding of CRP to degraded, nonoxidized LDL enhances complement activation. Arterioscler Thromb Vasc Biol 1999; 19:2348-54.
Art
Wissenschaftlicher Artikel/Review (Englisch)
Zeitschrift
Arterioscler Thromb Vasc Biol 1999; 19
Veröffentlichungsdatum
01.10.1999
ISSN (Druck)
1079-5642
Seiten
2348-54
Kurzbeschreibung/Zielsetzung

Complement activation occurs in temporal correlation with the subendothelial deposition of LDL during early atherogenesis, and complement also plays a pathogenetic role in promoting lesion progression. Two lesion components have been identified that may be responsible for complement activation. First, enzymatic degradation of LDL generates a derivative that can spontaneously activate complement, and enzymatically degraded LDL (E-LDL) has been detected in the lesions. Second, C-reactive protein (CRP) colocalizes with complement C5b-9, as evidenced by immunohistological studies of early atherosclerotic lesions, so the possibility exists that this acute phase protein also fulfills a complement-activating function. Here, we report that addition of LDL and CRP to human serum did not result in significant C3 turnover. Addition of E-LDL provoked complement activation, which was markedly enhanced by CRP. Binding of CRP to E-LDL was demonstrated by sucrose flotation experiments. Binding was Ca(2+)-dependent and inhibitable by phosphorylcholine, and the complement-activating property of E-LDL was destroyed by treatment with phospholipase C. These results indicated that CRP binds to phosphorylcholine groups that become exposed in enzymatically degraded LDL particles. Immunohistological studies complemented these findings in showing that CRP colocalizes with E-LDL in early human atherosclerotic lesions. Thus enzymatic, nonoxidative modification of tissue-deposited LDL can be expected to confer CRP-binding capacity onto the molecule. The ensuing enhancement of complement activation may be relevant to the development and progression of the atherosclerotic lesion.