TY - JOUR
T1 - Delivery of negatively charged liposomes into the atherosclerotic plaque of apolipoprotein E-deficient mouse aortic tissue
AU - Zhaorigetu, Siqin
AU - Rodriguez-Aguayo, Cristian
AU - Sood, Anil K.
AU - Lopez-Berestein, Gabriel
AU - Walton, Brian L.
N1 - Funding Information:
This work was supported by the Roderick D. MacDonald Research Fund at St. Luke’s Episcopal Hospital (10RDM008), NIH grants (UH2TR000943-01 and U54 CA151668), the RGK Foundation, and the Gilder Foundation. There is a provisional patent application (61844904) for this work. This manuscript underwent editing by Dr. Stancel of the Department of Scientific Publications at the Texas Heart Institute.
PY - 2014/9
Y1 - 2014/9
N2 - Liposomes have been used to diagnose and treat cancer and, to a lesser extent, cardiovascular disease. We previously showed the uptake of anionic liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits within lipid pools. However, the cellular distribution of anionic liposomes in atherosclerotic plaque remains undescribed. In addition, how anionic liposomes are absorbed into atherosclerotic plaque is unclear. We investigated the uptake and distribution of anionic liposomes in atherosclerotic plaque in aortic tissues from apolipoprotein E-deficient (ApoE-/ -) mice. To facilitate the tracking of liposomes, we used liposomes containing fluorescently labeled non-silencing small interfering RNA. Confocal microscopy analysis showed the uptake of anionic liposomes into atherosclerotic plaque and colocalization with macrophages. Transmission electron microscopy analysis revealed anionic liposomal accumulation in macrophages. To investigate how anionic liposomes cross the local endothelial barrier, we examined the role of clathrin-mediated endocytosis in human coronary artery endothelial cells (HCAECs) treated with or without the inflammatory cytokine tumor necrosis factor (TNF)-α. Pretreatment with amantadine, an inhibitor of clathrin-mediated endocytosis, significantly decreased liposomal uptake in HCAECs treated with or without TNF-α by 77% and 46%, respectively. Immunoblot analysis showed that endogenous clathrin expression was significantly increased in HCAECs stimulated with TNF-α but was inhibited by amantadine. These studies indicated that clathrin-mediated endocytosis is partly responsible for the uptake of liposomes by endothelial cells. Our results suggest that anionic liposomes target macrophage-rich areas of vulnerable plaque in ApoE -/- mice; this finding may lead to the development of novel diagnostic and therapeutic strategies for treating vulnerable plaque in humans.
AB - Liposomes have been used to diagnose and treat cancer and, to a lesser extent, cardiovascular disease. We previously showed the uptake of anionic liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits within lipid pools. However, the cellular distribution of anionic liposomes in atherosclerotic plaque remains undescribed. In addition, how anionic liposomes are absorbed into atherosclerotic plaque is unclear. We investigated the uptake and distribution of anionic liposomes in atherosclerotic plaque in aortic tissues from apolipoprotein E-deficient (ApoE-/ -) mice. To facilitate the tracking of liposomes, we used liposomes containing fluorescently labeled non-silencing small interfering RNA. Confocal microscopy analysis showed the uptake of anionic liposomes into atherosclerotic plaque and colocalization with macrophages. Transmission electron microscopy analysis revealed anionic liposomal accumulation in macrophages. To investigate how anionic liposomes cross the local endothelial barrier, we examined the role of clathrin-mediated endocytosis in human coronary artery endothelial cells (HCAECs) treated with or without the inflammatory cytokine tumor necrosis factor (TNF)-α. Pretreatment with amantadine, an inhibitor of clathrin-mediated endocytosis, significantly decreased liposomal uptake in HCAECs treated with or without TNF-α by 77% and 46%, respectively. Immunoblot analysis showed that endogenous clathrin expression was significantly increased in HCAECs stimulated with TNF-α but was inhibited by amantadine. These studies indicated that clathrin-mediated endocytosis is partly responsible for the uptake of liposomes by endothelial cells. Our results suggest that anionic liposomes target macrophage-rich areas of vulnerable plaque in ApoE -/- mice; this finding may lead to the development of novel diagnostic and therapeutic strategies for treating vulnerable plaque in humans.
KW - Atherosclerosis
KW - Endocytosis
KW - Human coronary artery endothelial cells
KW - Macrophage
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U2 - 10.3109/08982104.2013.863208
DO - 10.3109/08982104.2013.863208
M3 - Article
C2 - 24443972
AN - SCOPUS:84906226774
SN - 0898-2104
VL - 24
SP - 182
EP - 190
JO - Journal of Liposome Research
JF - Journal of Liposome Research
IS - 3
ER -