Abstract 10681: Nanoliposome Protection against AL Amyloid Light Chain Protein-Induced Endothelial Injury
Objective: A newly-recognized pathogenic mechanism underlying light chain amyloidosis (AL) involves endothelial dysfunction and cell injury caused by misfolded light chain proteins (LC). Nanoliposomes (NL) are artificial phospholipid vesicles that could attach to misfolded proteins and reduce tissue injury. Our aim is to test whether co-treatment with NL reduce LC-induced endothelial dysfunction and cell death.
Approach: Abdominal subcutaneous adipose arterioles from 9 non-AL subjects were cannulated; dilator response to acetylcholine and papaverine were measured at baseline and following 1-hour exposure to LC (20 μg/mL, 2 purified from AL subjects’ urine, 1 from human recombinant LC [AL-09]) ± NL (phosphatidylcholine/cholesterol/phosphatidic acid 70/25/5 molar ratio). Human aortic artery endothelial cells (HAEC) were exposed to Oregon Green-labeled LC±NL for 24 hours and intracellular LC and apoptosis (Hoechst stain) were measured. Circular dichroism spectroscopy were performed on AL-09 LC±NL to follow changes in secondary structure and thermal stability of the protein.
Results: see figure. LC caused impaired dilation to acetylcholine that was restored by NL (control-94.0±1.8%, LC-65.0±7.1%, LC+NL-95.3±1.8%, p≤0.001 LC vs. control or LC+NL) (Fig. 1A). NL protection was inhibited by L-NG-nitroarginine methyl ester. NL increased the beta sheet structure of LC (more negative ellipticity at 211-220 nM wavelength, p<0.001,Fig. 1B), reduced endothelial cell internalization of LC (Fig. 1C) and protected against LC-induced endothelial cell death (Fig. 1D).
Conclusions: LC induced human adipose arteriole endothelial dysfunction and endothelial cell death, which were reversed by co-treatment with NL. This protection may partly be due to enhancing LC protein structure and reducing LC internalization. Nanoliposomes represent a promising new class of agents to ameliorate tissue injury from protein misfolding diseases such as AL.
- © 2013 by American Heart Association, Inc.