Nanoliposomes protect against AL amyloid light chain protein-induced endothelial injury.
BACKGROUND
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.


OBJECTIVE
To test whether co-treatment with NL reduces LC-induced endothelial dysfunction and cell death.


METHODS
Abdominal subcutaneous adipose arterioles from 14 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) or NL alone. 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 was performed on AL-09 LC ± NL to follow changes in secondary structure and protein thermal stability.


RESULTS
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 versus control or LC + NL). NL protection was inhibited by L-NG-nitroarginine methyl ester. NL increased the beta sheet structure of LC, reduced endothelial cell internalization of LC and protected against LC-induced endothelial cell death.


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.
Phoenix Veterans Affairs , Phoenix, AZ , USA .
Seth
S
Truran
Volkmar
V
Weissig
Marina
M
Ramirez-Alvarado
Daniel A
DA
Franco
Camelia
C
Burciu
Joseph
J
Georges
Shishir
S
Murarka
Winter A
WA
Okoth
Sara
S
Schwab
Parameswaran
P
Hari
Raymond Q
RQ
Migrino
D000368:Aged; D000682:Amyloid / Q000737:chemistry*; D000686:Amyloidosis / Q000188:drug therapy*; D017209:Apoptosis / Q000187:drug effects; D004727:Endothelium / Q000187:drug effects* / Q000293:injuries / Q000473:pathology; D006333:Heart Failure / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D053758:Nanoparticles / Q000737:chemistry / Q000627:therapeutic use*; D057165:Proteostasis Deficiencies / Q000188:drug therapy
D000682:Amyloid; D008081:Liposomes