Binding of CD40L to Mac-1's I-Domain Involves the EQLKKSKTL Motif and Mediates Leukocyte Recruitment and Atherosclerosis-But Does Not Affect Immunity and Thrombosis in Mice

作者：Wolf Dennis; Hohmann Jan David; Wiedemann Ansgar; Bledzka Kamila; Blankenbach Hermann; Marchini Timoteo; Gutte Katharina; Zeschky Katharina; Bassler Nicole; Hoppe Natalie; Rodriguez Alexandra Ortiz; Herr Nadine; Hilgendorf Ingo; Stachon Peter; Willecke Florian; Duerschmied Daniel; von zur Muhlen Constantin; Soloviev Dmitry A; Zhang Li; Bode Christoph; Plow Edward F; Libby Peter; Peter Karlheinz^*; Zirlik Andreas

来源：Circulation Research, 2011, 109(11): 1269-U202.

DOI：10.1161/CIRCRESAHA.111.247684

• atherosclerosis
• inflammation
• CD40L
• Mac-1
• peptide inhibitor

Rationale: CD40L figures prominently in chronic inflammatory diseases such as atherosclerosis. However, since CD40L potently regulates immune function and hemostasis by interaction with CD40 receptor and the platelet integrin GPIIb/IIIa, its global inhibition compromises host defense and generated thromboembolic complications in clinical trials. We recently reported that CD40L mediates atherogenesis independently of CD40 and proposed Mac-1 as an alternate receptor.
Objective: Here, we molecularly characterized the CD40L-Mac-1 interaction and tested whether its selective inhibition by a small peptide modulates inflammation and atherogenesis in vivo.
Methods and Results: CD40L concentration-dependently bound to Mac-1 I-domain in solid phase binding assays, and a high-affinity interaction was revealed by surface-plasmon-resonance analysis. We identified the motif EQLKKSKTL, an exposed loop between the alpha 1 helix and the beta-sheet B, on Mac-1 as binding site for CD40L. A linear peptide mimicking this sequence, M7, specifically inhibited the interaction of CD40L and Mac-1. A cyclisized version optimized for in vivo use, cM7, decreased peritoneal inflammation and inflammatory cell recruitment in vivo. Finally, LDLr(-/-) mice treated with intraperitoneal injections of cM7 developed smaller, less inflamed atherosclerotic lesions featuring characteristics of stability. However, cM7 did not interfere with CD40L-CD40 binding in vitro and CD40L-GPIIb/IIIa-mediated thrombus formation in vivo.
Conclusions: We present the novel finding that CD40L binds to the EQLKKSKTL motif on Mac-1 mediating leukocyte recruitment and atherogenesis. Specific inhibition of CD40L-Mac-1 binding may represent an attractive anti-inflammatory treatment strategy for atherosclerosis and other inflammatory conditions, potentially avoiding the unwanted immunologic and thrombotic effects of global inhibition of CD40L. (Circ Res. 2011; 109: 1269-1279.)

• 出版日期2011-11-11