Abstract 16209: Clusterin-Nanoliposome Complex Attenuates Human Arteriole Endothelial Dysfunction Induced by AL Amyloid Light Chain Proteins
Endothelial dysfunction is an early pathology in AL amyloidosis involving misfolded light chain protein (LC) toxicity. Clusterin (Clu) is a chaperone protein that stabilizes misfolded proteins. Conjugating Clu to nanoliposomes (NL, phospholipid nanoparticles) may allow tissue-targeted Clu delivery. We aim to test the hypothesis that Clu complexed with NL will protect against LC induced arteriole endothelial dysfunction.
Methods: Urine LC were purified from 3 biopsy proven AL subjects. Clu was mixed with NL (74 mol% phosphatidylcholine, 25 mol% cholesterol, 1mol% stearyltriphenylphosphonium chloride). Ex-vivo subcutaneous adipose arterioles from subjects without vascular disease or AL were cannulated, constricted with endothelin-1 and baseline (control, C) dilator response was measured after exposure to 10-9-10-4M acetylcholine. Arterioles were then exposed for 1 hour to LC (20 µg/mL) ± Clu-NL (300 ng Clu/mL) and a second dilator response was measured. Effective dose concentration of acetylcholine producing 50% dilation (EC50) was computed. Separately, LC (50 µg/mL) were passed through Clu-containing (Clu+) or Clu-free (Clu-) affinity columns and the filtrate applied to human aortic endothelial cells (HAEC) for 1 hour. HAEC cell death was measured using DNA fragmentation ELISA.
Results: Maximum dilation was reduced with LC (86±4% C, 52±6% LC and 74±10% LC+Clu-NL, p<0.001 LC vs. C). LC increased acetylcholine EC50 that was attenuated by Clu-NL (Fig. A). HAEC treated with LC filtered through Clu- column showed increased DNA fragmentation while LC filtered through Clu+ column showed no increase (Fig. B).
Conclusions: LC caused human arteriole endothelial dysfunction which was attenuated by co-treatment with Clu-NL complex. The column filtration experiment suggests that Clu may protect against vascular cell injury by physicochemical sequestration of LC. Clusterin complexed to nanoliposomes is a promising novel biologic agent against LC toxicity.
- © 2012 by American Heart Association, Inc.